: The main goal of this proposal is to provide a comprehensive description of an entire reflex pathway in the mammalian enteric nervous system at the single cell level. This goal will be achieved by using an optical recording technique called multiple site optical recording of transmembrane voltage (MSORTV) on a mucosa- submucosa preparation. The reflex that will be studied is a local vasodilation that is produced in response to mechanical stimulation of the mucosa. Spike sorting analysis of raw optical data will be used the identify the patterns of activity involved in the reflex. Neural activity observed will be correlated with immunocytochemical identification of transmitter phenotype of neurons. These studies will help elucidate the pattern of connectivity within an enteric plexus.